In this paper, we investigate the advantages of multiple-input multiple-output (MIMO) faster-than-Nyquist (FTN) signaling under a fixed utilized bandwidth and multipath fading channels. We present derivations of the input-output relationships for MIMO-FTN systems and decompose the MIMO transmission scheme into spatial and spectral precoding procedures. An approximated frequency-domain equalizer (FDE) is introduced at the receiver as an effective solution to decode the signals. The simulation results reveal that FTN signaling outperforms conventional Nyquist signaling under the fixed-bit transmission in terms of the bit error rate (BER) and throughput. It is shown that FTN signaling has the applicability of a lower-level modulation process, which might decrease the peak-to-average power ratio (PAPR), while there exists a tradeoff between PAPR and BER/throughput. Moreover, the advantages of the approximated FDE and FTN-SCFDE systems are confirmed in the MIMO configuration.
